NAME
POE::Devel::ProcAlike - Exposing the guts of POE via FUSE
SYNOPSIS
#!/usr/bin/perl
use strict; use warnings;
use POE::Devel::ProcAlike;
use POE;
# let it do the work!
POE::Devel::ProcAlike->spawn();
# create our own "fake" session
POE::Session->spawn(
'inline_states' => {
'_start' => sub {
$_[KERNEL]->alias_set( 'foo' );
$_[KERNEL]->yield( 'timer' );
},
'timer' => sub {
$_[KERNEL]->delay_set( 'timer' => 60 );
}
},
'heap' => {
'fakedata' => 1,
'oomph' => 'haha',
},
);
# run the kernel!
POE::Kernel->run();
ABSTRACT
Using this module will let you expose the guts of a running POE program
to the filesystem via FUSE. This also includes a lot of debugging
information about the running perl process :)
DESCRIPTION
Really, all you have to do is load the module and call it's spawn()
method:
use POE::Devel::ProcAlike;
POE::Devel::ProcAlike->spawn( ... );
This method will return failure on errors or return success. Normally
you don't need to pass any arguments to it, but if you want to do zany
things, you can! Note: the spawn() method will construct a singleton.
This constructor accepts either a hashref or a hash, valid options are:
fuseopts
This is a hashref of options to pass to the underlying FUSE component,
POE::Component::Fuse's spawn() method. Useful to change the default
mountpoint, for example. Setting the mountpoint is a MUST if you have
multiple scripts running and want to use this.
The default fuseopts is to enable: umount, mkdir, rmdir, and mountpoint
of "/tmp/poefuse_$$". You cannot override those options: alias,
vfilesys, and session.
The default is: undef
vfilesys
This is a Filesys::Virtual::Async subclass object you can provide to
expose your own data in the filesystem. It will be mounted under /misc
in the directory.
The default is: undef
Commands
There is only a few commands you can use, because this module does
nothing except export the data to the filesystem.
This module uses a static alias: "poe-devel-procalike" so you can always
interact with it anytime it is loaded.
shutdown
Tells this module to shut down the underlying FUSE session and terminate
itself.
$_[KERNEL]->post( 'poe-devel-procalike', 'shutdown' );
register
( ONLY for PoCo module authors! )
Registers your Filesys::Virtual::Async subclass with ProcAlike so you
can expose your data in the filesystem.
Note: You MUST call() this event so ProcAlike will get the proper
caller() info to determine mountpath. Furthermore, ProcAlike only allows
one registration per module!
$_[KERNEL]->call( 'poe-devel-procalike', 'register', $myfsv );
unregister
( ONLY for PoCo module authors! )
Removes your registered object from the filesystem.
Note: You MUST call() this event so ProcAlike will get the proper
caller() info to determine mountpath.
$_[KERNEL]->call( 'poe-devel-procalike', 'unregister' );
Notes for PoCo module authors
You can expose your own data in any format you want! The way to do this
is to create your own Filesys::Virtual::Async object and give it to
ProcAlike. Here's how I would do the logic:
my $ses = $_[KERNEL]->alias_resolve( 'poe-devel-procalike' );
if ( $ses ) {
require My::FsV; # a subclass of Filesys::Virtual::Async
my $fsv = My::FsV->new( ... );
if ( ! $_[KERNEL]->call( $ses, 'register', $fsv ) ) {
warn "unable to register!";
}
}
Keep in mind that the alias is static, and you should be executing this
code in the "preferred" package. What I mean by this is that ProcAlike
will take the info from caller() and determine the mountpoint from it.
Here's an example:
POE::Component::SimpleHTTP does a register, it will be mounted in:
/modules/poe-component-simplehttp
My::Module::SubClass does a register, it will be mounted in:
/modules/my-module-subclass
Furthermore, ProcAlike only allows each package to register once, so you
have to figure out how to create a singleton and use that if your PoCo
has been spawned N times. The reasoning behind this is to have a
"uniform" filesystem that would be valid across multiple invocations. If
we allowed module authors to register any name, then we would end up
with possible collisions and wacky schemes like "$pkg$ses->ID" as the
name...
Also, here's a tip: you don't have to implement the entire
Filesys::Virtual::Async API because FUSE doesn't use them all! The ones
you would have to do is: rmtree, scandir, move, copy, load, readdir,
rmdir, mkdir, rename, mknod, unlink, chmod, truncate, chown, utime,
stat, write, open. To save even more time, you can subclass the
Filesys::Virtual::Async::inMemory module and set readonly to true. Then
you would have to subclass only those methods: readdir, stat, open.
TODO
* tunable parameters
Various people in #poe@magnet suggested having a system where we
could do "sysctl-like" stuff with this filesystem. I'm not entirely
sure what we can "tune" in regards to POE but if you have any ideas
please feel free to drop them my way and we'll see what we can do :)
* pipe support
Again, people suggested the idea of "telnetting" into the filesystem
via a pipe. The interface could be something like PoCo-DebugShell,
and we could expand it to accept zany commands :)
* module memory usage
I talked with some people, and this problem is much more complex
than you would think it is. If somebody could let me know of a
snippet that measures this, I would love to include it in the perl
output!
* POE::API::Peek crashes
There are some functions that causes segfaults for me! They are:
session_memory_size, signals_watched_by_session, and
kernel_memory_size. If the situation improves, I would love to
reinstate them in ProcAlike and expose the data, so please let me
know if it does.
* more stats
More stats are always welcome! If you have any ideas, please drop me
a line.
EXPORT
None.
SEE ALSO
POE
Fuse
Filesys::Virtual::Async
SUPPORT
You can find documentation for this module with the perldoc command.
perldoc POE::Devel::ProcAlike
Websites
* AnnoCPAN: Annotated CPAN documentation
* CPAN Ratings
* RT: CPAN's request tracker
* Search CPAN
Bugs
Please report any bugs or feature requests to "bug-poe-devel-procalike
at rt.cpan.org", or through the web interface at
. I
will be notified, and then you'll automatically be notified of progress
on your bug as I make changes.
AUTHOR
Apocalypse
Props goes to xantus who got me motivated to write this :)
COPYRIGHT AND LICENSE
Copyright 2009 by Apocalypse
This library is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.